1. Field of the Invention
The present invention relates in general to a method of adjusting the rotation speed of an optical disc drive. In particular, the present invention relates to a method of automatically decreasing rotation speed of the spindle motor in response to the data transmission rate when the read data is MP3 data.
2. Description of the Related Art
With the advances in the operational speed of personal computers, the transmission rate and capacity of peripheral units has also improved. Thus, the function of various storage media of the computer has progressed from simple data storage, to numerous other purposes. Using a CD-ROM optical disc drive as an example, the recorded content in the optical disc may be audio video or standard data. There are many types of data format that can be recorded on the optical disk.
CD-DA: CD-DA(Compact Disc Digital Audio) is the standard format for music CDs. All CD optical discs conforming to the CD-DA standard can be played by CD audio player.
Mode 1: Each sector comprises error correction code (ECC) with a size of 2048 bytes. ECC can fix the reading error of data when data is read from the optical disc to increase the accuracy of data writing. The data structure in Mode 1 is employed when errors are not allowed in the stored data, for example, software, games, and archived data.
Mode 2:Mode 2 comprises the two forms described below.
Form 1: Form 1 uses error detection code (EDC) and error correction code (ECC) to encode data. Thus, data is encoded with high accuracy by Form 1 of Mode 2.
Form 2: Form 2 uses no error detection code (EDC) or error correction code (ECC) to process the data to be written. Thus, the accuracy of the data in Form 2 of Mode 2 is lower than in Model or Form 1 of Mode 1. For example, VCD data is encoded in Form 2 of Mode 2.
However, the transmission rate between the host and optical disc drive mostly depends on the time expended by the optical disc drive in reading the optical disc. Thus, there is a trend to increase the data reading rate of the optical disc drive. The conventional method improves the data reading rate by setting the spindle motor of the optical disc to rotate at the highest speed when reading data. However, the conventional optical disc drive still uses the highest speed to play MP3 data because does not recognize the read data as MP3 data. Thus, the spindle motor operating at high speed consumes excessive power. In addition, high speed operation of the optical disc results in noise, vibration, and poor reading performance and causes the performance of the conventional optical disc drive to deteriorate.